Water Resource Simulation in an Arid Watershed Considering an Allocation for Dust Stabilization and Different Scenarios of Water Supply and Demand

Abstract

Water is the main demand of people settled in the arid areas of large watersheds.<br />This demand is more necessary and critical in the areas with the potential of dust<br />sources and fine sediments entering into the watershed in a long-time period. Sistan<br />watershed to the south-east of Iran is a region with the specific hydrological<br />conditions. The 120-day winds blow continuously in the summer propagating large<br />amounts of dusts directly into the cities and rural areas. In this study, a demand is<br />considered for the dust stabilization in the study area. A field surrounding the<br />watershed that directly affects the amount of dusts is selected. The amount of water<br />demand that is needed for the stabilization and saturation of the soil is measured by<br />the soil sampling and experimental on-site works. A demand for dust stabilization is<br />defined and the water resources systems are simulated. Different scenarios of water<br />supply and demand are considered. Results show the unmet demands of the different<br />scenarios (Sc) in a 15-year period in the region. The highest amount of unmet water<br />demand is calculated for the scenario No.10 that is the combined effects of reducing<br />agricultural land use and increasing the agricultural efficiency and reducing<br />evaporation from Chahnimeh reservoir and flow of discharge in accordance with the<br />agreement between Iran and Afghanistan enforced in 2015. Different scenarios are<br />evaluated in terms of dust stabilization priority and also agriculture using the analytic<br />hierarchy method. This shows the high score of Scenario No.9 that is the combined<br />effect of reducing agricultural land use and the increasing the agricultural efficiency<br />and reducing the evaporation from Chahnimeh.